An MCP server connects your agents to tools and outside services — like Linear or Slack — so they can do more than edit code. This article covers the two ways to add one, how authentication works, and where to manage them.
Two ways to add an MCP server
- From a plugin. Many services ship their MCP server as a plugin — Linear's plugin, for example, is essentially just its MCP server. Pull the plugin in from a marketplace (see Skills & plugins) and it shows up among your MCP servers, ready to use.
- Your own definition. To connect something custom, add it yourself on the Plugins page under MCP Servers → New MCP Server. Choose the type — a local Command or an HTTP endpoint — give it a name and description, provide the command and arguments (or URL), and optionally set it to be enabled by default.
Authentication
By default, the app manages authentication for you through a proxy, so a connected MCP server works for both Claude and Codex with no extra setup. You can turn the proxy off under Settings → MCP Servers, but then you handle auth with each agent yourself — Claude and Codex each have their own system for it. Leave the proxy on unless you're already set up with the provider directly.
One caveat: Slack has unusual MCP authentication requirements that the managed proxy doesn't cover, so connecting Slack needs extra setup on your side.
Where to manage them
MCP servers live on the Plugins page, under MCP Servers, alongside your skills, collections, and marketplaces. Inside a chat, you can enable or disable a connected server for that conversation like any other tool.
Next steps
- Skills & plugins — import plugins (many bundle an MCP server) and manage them in one place.
- Core concepts & vocabulary — the terms behind these tools.